The frame is solidly built. Corner stiffeners work quite well to stabilize it. Adjusted mine to 32” depth, so top cover (not adjustable:-) doesn’t cover all, but a piece of plywood on top would fix that that. Only problem is the wheel attach. It looks like it’s a spot-welded nut. I’ve only loaded to 80lbs and one has already broken loose. When done, load will be close to 180lbs (it’s rating) so I will have to reinforce somehow. Update: Three wheel attach nuts have failed. Not even fully loaded. It looks like they punched out a hex hole for the nut to sit in then spot welded it! If it were a full weld, it might have worked, but just a round clearance hole with the nut spot welded on surface would have been stronger (would have frame support stress rather than spot welds). Now I have to use two large pattern washers to compensate for the hex hole.